Assembly



Jan. 15, 1952 H, G, WElGl-{TMAN Re. 23,454

RESONANT MAGNETIC SWITCH ASSEMBLY Original Filed Aug. 14, 1946 /8 9 Fig.5.

INVENTOR. Hfs/eager 6. L/E/@Hm/M/ Reissued Jan. 15, 1952"nE'soNANrYMAGNE'rIc SWITCH ASSEMBLY Herten G. weigmman, Berkeley. cam.,assignmto Stevens-Arnold Inc., Boston, Mass., a. corpov ration ofMassachusetts Original No. 2,471,594, dated May 31, 1949, Serial No.690,387, August 14, 1946. Application for reissue May 17, 1950, SerialNo. 162,596

sciame. (o1. zoos-91) Matter enclosed in heavy bracketsl Il appears inthe original patent but forms'no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates to electric switches having resonant armatureswhich close electric circuits when alternating currents having thefrequencies to which their armatures are resonant, are supplied throughtheir energizing coils, and which are known generally, as resonantswitches.

Prior resonant switches for performing the duties for which thisinvention was devised, utilized pairs of. resonant armatures supportedas cantilever beams from the opposite sides yof sealed glass envelopes.Such switches were not'only' costly but their desired resonantfrequenciesI in mass produced switches, were difllcult to main-l tain.

This invention provides a resonant switchy which utilizes but asingleresonant armature for each frequency to which' the switch isresponsive, and which is less expensive and more `efllcient than theprior switches. f

Objects of the invention are to improve the performance of, and toreduce the cost `of, `rese-z nant switches. y

The invention will now be described with ref-l erence to the drawing, lfwhich: .Y v

Fig. 1 is a plan view looking downwardly upon an assembled switchembodying thisK invention; y

Fig. 2 is a plan view similar to Fig.` 1 but with a portion of theenergizing coil removed;

Fig. 3 is a sectional view along the linesV 3 3 ofFig.2,and Fig. 4 is aplan view with a portion ofthe energizing coil removed, of anotherswitch embodying this invention, and having two'arma' tures resonant atdii'lerent frequencies. Referring first to Figs. 1, 2 and 3, the metalchannel member 5 has the perpendicular extensions 6 with the turnedoverears 1 at one end. which extend over and support in position',l thepermanent magnet 8 against the'contact member 9 of magnetizable metal,and the wrapper' I of electric insulation around the magnet and thecontact member. The extensions 6 of the .chan-y nel member 5 have theturned over ears II at their other end, and which extendover and supportin position, the brass ller block I2 vagainst the fixed end I3 of thearmature I4 of magnetizable spring metal. a v f The contact member 9 hasa perpendicular ex, tension I5 with the vcontact surface I6 thereonadjacent and normally spaced from the contact surface I1 on the adjacentside of the free end of the armature I4 whichuis seen to be supported asa cantileverbeam, a, I

supported on th The coil form IB is A membe 's' around cheariature 14;and has 2 y wound thereon the energizing coil I9 which is adapted to beconnected by the wires 20 toasource of alternating current.

The fixed end I3 of the armature I4, outer end of the contact member 9are adapted to be connected to an electric circuit for closing same whenthe contact surface` I'I of the armature I4 strikes the contact surfaceI6 of the contact member 9.

The armature I4 is resonant at a. selected fre` quency which, by way ofexample, may be llili) cycles per second, and when alternating currentof that frequency is passed through the coil I9, the deflection of thearmature will be sufficient to cause the contact surface I'I vto strikethe contact surface I6.

The armature I4 is magnetized by the vcurrent flowing through the coilI9 whereby the free end ofthe armature will alternately be attracted`tol and released by, the inner end of the contact member 9. the contactmember 9 whereby the free end of the armature is `attracted therebywhenY no curv-` rent is flowing through the energizing coil, thusbiasing the free end of the armature towards the contactl member,` Ihecoil magnetizes the armature -to the opposite polarity during thehalf-cycles the magnetic field of the coil opposes that of the magnetwhereby the armature is repelled by the contact member. During the otherhalf-cycles, the magnetic fields of the coil and of the'magnet are inaiding relationproviding increased attraction between the'free end ofthe armature and the contact member. This provides greater armaturemovement andm'ore positive contact. 'A Y. Another function of the magnetB'is" toadjust precisely the resonant frequency of 'the armature I4. Themagnet attracts the free end of the armature andv opposes its ffreed'omto vibrate thereby adding efiectivelstiffn'ess to' the armature. v Dueto inequalities in material, two"sir`ni1ararmatures may" have differentresonant frequencies. But by slidably positioning the magnet 8 towardsor away from'the fie end of the arma'- ture during the assemblylof theswitch, the effecniet:itert s has itsinn'er end n* extending between 1and thei The magnet B initially magnetizesv the free ends of thearmatures 3U and 3| with its contact surface 33 spaced from the contactsurface 34 of the armature 3|), and with its contact surface 35 spacedfrom the contact surface 3B of the armature 3|; the planes'of thearmatures and the contact member are perpendicular in the channel memberto those of Figs. L-3, and one of the wires 2| is connected to the brassblock I2 instead of to the xed end of one of the armatures. f i

The wires 2| are adapted to connect both armatures 30 and 3|, and thecontact member 9 of Fig. 4 to an electric circuit to be closed. Thearmature 30 is seen to be longer than l,the armature 3| whereby it isresonant at a lower frequency. Thus the electric circuit to which thewires 2| of Fig. 4 are connected, will be closed whenv current havinglthe .frequency to which, the armature 30 isI resonant, ispassed-through the coil I3, and when current having the frequency towhich the armature 3| is resonant, is passed through the coil. Or if theresonance curves of the two overlap, the circuit to be closed bytheswitch, will be closed at any frequency infthe band of frequenciesYcovered by the overlapping resonance curves; y i

An advantage of the embodiment of Fig. 4, 1n addition to providing tworesonant armatures in one switch, is that the two armatures, aremagnetized alike by their energizing coil resulting in their free endshaving the same magnetic poles and thereby repelling each other thusbiasing 4 bent over at one end thereof for supporting said filler blockand said armature in said channel member; other extensions on said sidesbent over at -the other end ythereof for supporting said in-Asulation,said magnet and said contact member `in said channel member,and an energizing coil suppQIted karound said channel member formagnetizing' said armatura said free end ofV said armature being adaptedto strike said contact `member andfto close an electric circuitconnected thereto and to said armature when alternating current havingthe resonant frequency of said t armature is passed through said coil.

them away from the contact member and providing greater armaturemovement.

Another advantage of the switch of Fig. 4 is that since the magneticmember 9 to which they are attracted and by which vthey are re'pelledwhen Aalternating current is supplied to their energizing coil, isbetween the two armatures, their movements are 180 out of phase, and thevibrations of the switch caused by the motion of one armature arereduced by the oppositely phased motion of the other armature wherebythe mass of the block I2, and of the switch can be substantiallyreduced. This advantage is so great that -it is preferred that evenwhere the switch is intended to be resonanty at only one frequency, the`two armatures and 3| be used with the contact surface being omittedfrom one. In such a case both armatures preferably would be resonant atsubstantially the same frequency.

While embodiments of the invention have been described for the` purposeof illustration, it should be understood that the invention-is notlimited to the exact apparatus and arrangement of apparatus illustrated,as modifications thereof may be suggested by those skilled in the artwithout departure from the essence of the invention.

What is claimed is:

l. A resonant switch comprising a channel member having a base, andsides extending Subfstantially perpendicular to said base; an armatureof magnetizable spring metal; means ln cluding a i'lller block forsupporting Said armature as a cantilever beam in one end of said channelmember; a contact member of mag' netizable metal Ain the other end o fsaid channel member and having its inner end overlapping and spaced fromthe free end of said armature; a permanent magnet alongside said contactmember and having its inner end closely spaced from said free end ofsaid armature; insulation around said contact member andsaid magnet forinsulatingH same from said' channel member; ex-

2.Av resonant switch comprising a channel member having a'base, andsides extending substantially perpendicular thereto; an armature ofmagnetizable spring metal having a rst portion contacting- .sgid has?.inves and of said member, ,having -a secondmrtion extendingSubstantially perpendicular to said ilrst portion, and a third portionextending as a cantilever beam towards the other end of said member; aller block on said rst portion having its inner end contacting saidsecond portion; extensions on said sides bent over against said fillerblock lfor supporting same and said armature in said -member;'a contactmember of magnetizable metal in the other end of said member, saidcontact member having a rst DOrtion extending substantially parallel tosaid base, and having a second, inner portion extending substantiallyperpendicular to said base and overlapping and spaced 4from said ,freeend of said armature; a permanent magnet on said first portion of saidcontact member and having its inner end closely spaced from said freeend of said armature; insulation around said magnet and said lrstportion of said contact member for insulating same from said channelmember; other extensions on said sides bent over against said insulationfor supporting same, said` magnet and contact member in said channelmember, and an energizing coil supported around said channel member formagnetizing `said armature, said free end of said armature being adaptedto strike said inner portionof said contact member, and to close anelectric circuit connected thereto and to said armature when alternatingcurrent having the resonant frequency of said armature is passed throughsaid coil. y

3. A resonant switch as claimed lin claim 1 in which the fixed end ofthe armature is anchored in -the filler block, andin which anotherflexible reed armature of magnetizable metal spaced from said armaturehas one end anchored in said block.

4. A magnetic switch vcomprising a channeled base having a closed side,amV opposite open side, and spaced, substantially parallel closed sidesextending perpendicular to said first closed side, a,

' flexible reed L] armature member of magnetizping the other end of saidarmature member,

means for supporting the other end of said con-` tact member in theother end of said base, said last mentioned means including extensionsfrom said parallel sides bent over towards each other substantiallyperpendicularv to saidr parallel sides, means insulating one of saidmembers from ySaid base, Said basebens of metal, and an eingrsizing coil[supprted around said base] around said members and having its end.,supported from said extensions, said members extending between said openside and said #rst mentioned closed side. 5

HERBERT G. WEIGHTMAN.

REFERENCES CITED The following references are of record in the lo nle ofthis patent or the original patent:

`UNITED STATES" PATENTS Number Name Date Potter Oct. 8, 1901 Fell Sept.9, 1902 Hartman-Kempf July 4, 1911 Dean Mar. 3, 1914 Waller Oct. 18,1932 Crum Oct. '7, 1941 Marrison May 1, 1945 Ray Aug. 7, 1945 MathesJan. 21. 1947

